This invention relates in general to a tensioner for a conveyor belt scraper assembly and, more particularly, to a low-profile tensioner that utilizes an elastomeric collar having a series of spokes, wherein the elastomeric collar is tensioned and then connected to the rotatable shaft of the conveyor belt scraper assembly to bias the scraper against the surface of the conveyor belt while providing adequate space around the tensioner to allow for the easy adjustment or maintenance of the tensioner.
Transportation of materials or products to remote locations or along a production line, such as in the mining or manufacturing industries, is often accomplished through the use of conveyor belts. In use, employees or machines place the materials or products on the conveyor belt at one location and the conveyor belt carries those goods to another location for further processing or unloading. During the process, particles frequently accumulate on the conveyor belt surface. Without the removal of the particles, the conveyor belt may become inoperative. Thus, a conveyor belt scraper is often used to remove the particles from the conveyor belt surface. As the scrapers, which are often polyurethane, will wear down from continued use, it is important to ensure that the belt scraper remains in contact with the conveyor belt surface to remove the particles.
Heretofore, it has been known to use tensioning devices utilizing torsion tubes or mechanical springs to bias the conveyor belt scraper into engagement with the conveyor belt surface. For example, U.S. Pat. No. 4,533,036 teaches the use of an elastomeric torsion tube that may be twisted and then connected to a collar attached to the rotatable shaft. The torsion tube of this tensioner needs to be of a certain length to allow for the creation of a sufficient torsional force to continually bias the scraper blade against the conveyor belt surface. Thus, it was sometimes difficult to adjust or maintain the tensioner because of the limited clearance or space between the tensioner and a wall or structure located adjacent to the conveyor belt structure.
Problems also occurred with the use of mechanical springs as tensioners. In particular, as the environment in which conveyor belt scrapers are used is often wet, dirty and corrosive, problems arose due to the buildup of particles or dirt between the coils of the springs or because of the corrosion of the spring. Additionally, the limited travel of the springs commonly required subsequent adjustments to the tensioners to ensure that the belt scrapers engaged their respective conveyor belt surface.
Therefore, there is a need for a low-profile tensioner that avoids the above problems and allows for the adjustment or maintenance of the tensioner while insuring that the belt scraper remains in contact with the conveyor belt surface to effectively scrape the conveyor belt.
The tensioner of the present invention overcomes the above problems in providing a low-profile tensioner that allows for adequate space to adjust and maintain the tensioner, while maintaining the scraper blade in contact with the conveyor belt surface. The tensioner is used with a conveyor belt scraper assembly that includes a conveyor belt scraper attached to a rotatable shaft that extends transversely and in spaced relation to the surface of the conveyor belt. At one end, the rotatable shaft extends through a fixed member and the tensioner. The tensioner, which is attached to the fixed member through a rigid collar, includes an elastomeric collar that has a series of spokes connecting an inner ring to an outer ring. A sleeve, connected at its base to the inner ring, extends through the elastomeric collar and is sized to allow the rotatable shaft to pass through.
Once the tensioner is assembled over the rotatable shaft and connected to a fixed member, the rotatable shaft is rotated until the scraper blade engages the conveyor belt surface. A tensioner wrench or other tool then may be used to load the elastomeric collar so that a torsional force is applied to the scraper blade shaft. The collar includes an outer ring connected to the fixed member, an inner ring concentric to the outer ring and connected to a sleeve receiving the shaft, and spokes interconnecting the rings. With the scraper blade biased against the conveyor belt surface, a locking pin or other device is used to connect the sleeve and inner ring of the elastomeric collar to the rotatable shaft, thereby acting to bias the scraper blade against the conveyor belt surface.
It is therefore an object of the present invention to provide a new and improved tensioner for a conveyor belt scraper that is compact and of a low-profile to minimize the space required in a conveyor installation and facilitate the adjustment and maintenance of the tensioner.
A further object of the present invention is to provide a new and improved conveyor belt scraper tensioner that utilizes a collar made of an elastomeric material having excellent wear characteristics, thereby increasing the life of the tensioner.
It is still a further object of the present invention to provide a new and improved conveyor belt scraper tensioner that utilizes an elastomeric collar having spokes connecting an inner ring to an outer ring to provide a low-profile tensioner that maintains the scraper blade in biased contact with the conveyor belt surface.
A still further object of the present invention is to provide a new and improved conveyor belt scraper tensioner that utilizes an elastomeric material having excellent memory characteristics to ensure that the scraper blade remains engaged with the conveyor belt surface as the scraper blade wears down.